Because He is the great I AM;

I am the salt of the earth. (Matthews 5:13)
I am the light of the world. (Matthews 5:14)
I am a child of God. (John 1:12)
I am part of the true vine, a channel (branch) of Christ's life. (John 15:15)
I am Christ's friend. (John 15:15)
I am chosen and appointed by Christ to bear His fruit. (John 15:16)
I am a joint-heir with Christ, sharing His inheritance with Him. (Romans 8:14-15)
I am a temple of God. His Spirit dwells in me. (1 Corinthians 3:16)
I am joined to the Lord and am one spirit with Him. (1 Corinthians 6:17)
I am a member (part) of Christ's body. (1 Corinthians 12:27)
I am a new creation. (2 Corinthians 5:17)
I am reconciled to God and am a minister of reconciliation. (2 Corinthians 5:18,19)
I am a saint. (Ephesians 1:1)
I am blessed with every spiritual blessing in heavenly places. (Ephesians 1:3)